Baby Boomers dropped out in record numbers. Now many are finding spiritual homes again -- and American religion will never be the same.

Back in the early 1960s, when cars were big and hair was short and families that prayed together stayed together, the Walceks said grace before meals and went to Mass every single morning. Emil and Kathleen sent their nine children to the local parochial schools in Placentia, California, and on Sunday mornings at St. Joseph's the family took up two pews.

Then one by one, the children set off on their spiritual travels, and in the process perfectly charted the journey of their generation. Emil Jr., 45, and Edward, 32, dropped out of church, and stayed out. John, 43, was married...